Regular or Premium Fuel?

[hill7410]

Should i Run premium or reg. in my atv? does it make that big of a difference since mine is efi?

[Scott K]

I would run whatever your owners manual says to run. Some people will say there is a bennifit to run premium, I tried it both, didnt notice a difference either way. I will stick to the cheep stuff.

[IndyEFI500]

Ditto to wandering eyes. I usually run the cheap stuff and don't notice any degredation or any improvement on the hig dollar stuff either.

[Roofer]

The only benefit to higher octane is that it stays better longer in the tank. Besides that, on a stock atv, 87 actually burns better than 91-93. Higher octane burns slower than 87, so then we can assume less power, right.

[BobT]

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The only benefit to higher octane is that it stays better longer in the tank. Besides that, on a stock atv, 87 actually burns better than 91-93. Higher octane burns slower than 87, so then we can assume less power, right.

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Absolutely not!!!

Higher octane does not translate into longer shelf life. Slower burning does not translate into less power. Diesel fuel burns considerably slower than gasoline but I guarantee my diesel will pack far more power in most situations. It comes down to stroke length being well matched with fuel burning rates, engine timing, etc.

Burn what your manufacturer suggests. Your engine is timed to run that fuel and running different fuel could cause damage and decreased performance. In many if not most cases, burning high octane in an engine designed for low ocatane fuels will result in poorer mileage not better.

Bob

[Uncle Bill]

This questions been beat to death a hundred times.

Hope this helps.

http://auto.howstuffworks.com/question90.htm

[Bjjams]

On my honda with efi it is recommended to put 86 octane or higher. I have always put in 87. Start giving her the good stuff and she'll expect to be treated like a princess.

[Roofer]

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The only benefit to higher octane is that it stays better longer in the tank. Besides that, on a stock atv, 87 actually burns better than 91-93. Higher octane burns slower than 87, so then we can assume less power, right.

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Absolutely not!!!

Higher octane does not translate into longer shelf life. Slower burning does not translate into less power. Diesel fuel burns considerably slower than gasoline but I guarantee my diesel will pack far more power in most situations. It comes down to stroke length being well matched with fuel burning rates, engine timing, etc.

Burn what your manufacturer suggests. Your engine is timed to run that fuel and running different fuel could cause damage and decreased performance. In many if not most cases, burning high octane in an engine designed for low ocatane fuels will result in poorer mileage not better.

Bob

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Sorry, didn't mean to say the higher octane gives it better shelf life, but higher octane fuel is normally non-oxygenated which makes it stay better longer.

You can't compare a diesel in this situation.

Higher octane fuel will not give you more power in a stock machine. In a modded, stroked, ported, or new ignition, then it depends on alot of things, but then you will see power gains.

[spearchucker]

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The only benefit to higher octane is that it stays better longer in the tank. Besides that, on a stock atv, 87 actually burns better than 91-93. Higher octane burns slower than 87, so then we can assume less power, right.

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Absolutely not!!!

Higher octane does not translate into longer shelf life. Slower burning does not translate into less power. Diesel fuel burns considerably slower than gasoline but I guarantee my diesel will pack far more power in most situations. It comes down to stroke length being well matched with fuel burning rates, engine timing, etc.

Burn what your manufacturer suggests. Your engine is timed to run that fuel and running different fuel could cause damage and decreased performance. In many if not most cases, burning high octane in an engine designed for low ocatane fuels will result in poorer mileage not better.

Bob

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Sorry, didn't mean to say the higher octane gives it better shelf life, but higher octane fuel is normally non-oxygenated which makes it stay better longer.

You can't compare a diesel in this situation.

Higher octane fuel will not give you more power in a stock machine. In a modded, stroked, ported, or new ignition, then it depends on alot of things, but then you will see power gains.

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You are correct about the non-oxygenated fuel, but be careful, not all premium is non-oxygenated. All fuel in MN has ethanol unless is specifically says it doesn't on the pump.

[castmaster]

I always make sure to find a station that sells the stuff marked for off road and small engine use.

[BobT]

It has been my understanding that it is unlawful to use non-oxygenated fuel in your car unless it is licensed for approval such as pre-ethanol collector vehicles.

I don't know what the fine is for getting caught but just an example. I drive a diesel and have been told that if I get caught with so much as a trace of the off-road red dye in my fuel tanks it will cost me a $1,000 fine plus $100 per gallon capacity of my vehicle. Since my vehicle has dual tanks with a total of about 45 gallons, this would be a $5,500 fine. Not worth it.

Bob

[Johnny_Namakan]

It is not illegal to use non-oxy fuel in your car. The reason it is illegal to use the off-road diesel is because it does not have the same taxes applied to it. Hence the reason it is cheaper. The off-road diesel is for off-road purposes (e.g. skid-steers, loaders, tractors, etc.)so highway taxes should not have to be paid by something that will never touch a highway. The non-oxy fuel does have all the same applicable taxes as the oxygenated and therefore the state/feds are still receiving their "dues." And as stated, not all premium fuels are non-oxy. It must have the white label stating non-oxygenated fuel for use in collectors........yada yada.

To answer the question though, I use premium or if possible the non-oxy where available. I even have to use the 89 octane stuff in my Dodge Hemi. Owner manual on my Dodge states that 89 octane or higher is recommended but it also states that 91 or 92 octane is not required and not recommended and may reduce performance. Just thought I'd throw that out there

[LMITOUT]

My Grizzly manual states that the engine was designed for 86 or higher.

It also states that gas containing ethanol can be used if it doesn't exceed 10% ethanol. That is the same recommendation that's in the manual for my 90HP Yamaha 4-stroke on my boat. What that tells me is that since our pumps are mandated at 10%, I'm using non-oxy. Costs a bit more, haven't had any performance issues, and the manufacturer doesn't suggest using it and I agree. Evidently the manufacturers of these engines know more than our wise legislatures that mandate this garbage. Go figure.... Who would you trust?

[firemedic5586]

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Should i Run premium or reg. in my atv? does it make that big of a difference since mine is efi?

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You want a high enough octain rating to keep you engine from "pinging". In MN we like corn, so with corn gas you need a tad higher rating then you would with strait gass. I've been told ETOH from corn also has a tendency to not have as long of a shelf life which can be a problem. Whats worse is corn gas can end up having gooo grow in it. Me I don't like the thought of goo growing in my fuel tanks. Especialy when it could strand me miles in the woods by myself. In a fast current of water above a (Contact Us Please), water fall, or while being chased by a boat load of zombies. This leaves The super pump for me that has the non-oxegenated gas. The higher octain rating will burn a bit hotter then what your average machine will need and you woun't get the full bang for your buck from it. But it wount't grow goo also.

[spearchucker]

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Should i Run premium or reg. in my atv? does it make that big of a difference since mine is efi?

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You want a high enough octain rating to keep you engine from "pinging". In MN we like corn, so with corn gas you need a tad higher rating then you would with strait gass. I've been told ETOH from corn also has a tendency to not have as long of a shelf life which can be a problem. Whats worse is corn gas can end up having gooo grow in it. Me I don't like the thought of goo growing in my fuel tanks. Especialy when it could strand me miles in the woods by myself. In a fast current of water above a (Contact Us Please), water fall, or while being chased by a boat load of zombies. This leaves The super pump for me that has the non-oxegenated gas. The higher octain rating will burn a bit hotter then what your average machine will need and you woun't get the full bang for your buck from it. But it wount't grow goo also.

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Most of what you say is not true. Don't get me wrong, I am not an ethanol lover, but I wanted to clear up some things.

1. Ethanol increases the octane of fuel, so therefore you don't need a higher octane if using ethanol blended fuel.

2. Higher octane fuel doesn't burn hotter or have more energy content than lower octane fuel. Octane is simply a measure of a fuels resistance to self detonation or "pinging"

3. Ethanol doesn't have "goo" in it. It will turn to "goo" if it sits for too long in an unsealed can. It will collect water which is what the "goo" is. If I used ethanol blended fuel, I buy it in quantities that I will use up within a month. If it needs to sit longer I used non-ethanol fuel and treat it with Seafoam as a stabilizer. The only really bad thing about ethanol in small engines is that it doesn't store well for more than a month or 2.

4. Ethanol has a slightly lower energy content than gasoline, so you will get a little less mileage with ethanol.

[firemedic5586]

C/P From Spearchucker's post with my replies

Most of what you say is not true. Don't get me wrong, I am not an ethanol lover, but I wanted to clear up some things.

1. Ethanol increases the octane of fuel, so therefore you don't need a higher octane if using ethanol blended fuel.

I beg to differ with you . The octane number scale is defined by two pure chemical reference fuels: normal heptane (n-heptane) with an octane number of zero, and isooctane (2,2,4-trimethylpentane) with an octane number of 100. The octane number of a blend of these two compounds is equal to the volume percentage of isooctane it contains. Isooctane also defines 100 on the performance number scale. The performance number scale above 100 is defined by mixtures of isooctane and tetraethyl lead.

2. Higher octane fuel doesn't burn hotter or have more energy content than lower octane fuel. Octane is simply a measure of a fuels resistance to self detonation or "pinging"

You are correct~~~ What I ment to say about the higher octane fuel “burning hotter” was that NON-oxygenated gas has more BTU’s in it then a mixed gas so it will burn hotter, yet your average machine will not be able to capitalize on that extra power. However in the owners manual that came with my machine it stated that if your using ethanol blended gas to use a mid grade octane rated fuel. This is due to "Fuel Leaning" Oxygenated gasoline leans the air-fuel mixture of carbureted engines and fuel injected engines that don't have an electronic control module (ECM) (see Chapter 5, Gasoline Engines). Engines with ECMs become fuel lean when the ECM is not controlling — when the engine is cold or the vehicle is being accelerated rapidly. The rest of the time, the ECM adjusts the air-fuel ratio to compensate for the oxygen in the fuel. If a carburetor is set to provide a very fuel-rich mixture, fuel leaning might improve performance. Otherwise, fuel leaning can degrade driveability; the extent depends on the engine's calibration.

Ethanol has a higher heat of vaporization than ethers. Some of the degradation in driveability of gasoline oxygenated with ethanol can be attributed to the additional heat needed to vaporize the fuel.

3. Ethanol doesn't have "goo" in it. It will turn to "goo" if it sits for too long in an unsealed can. It will collect water which is what the "goo" is. If I used ethanol blended fuel, I buy it in quantities that I will use up within a month. If it needs to sit longer I used non-ethanol fuel and treat it with Seafoam as a stabilizer. The only really bad thing about ethanol in small engines is that it doesn't store well for more than a month or 2.

Sorry, I disagree again~~~ "Water Tolerance" Conventional gasoline, depending on its aromatics content, can dissolve up to 150 parts per million (ppm) water at 21°C (70°F). Oxygenating gasoline with ethers can increase water solubility to 600 ppm. Contacting either conventional gasoline or ether-oxygenated gasoline with additional water will not affect the properties of the gasoline but can make it hazy in appearance.

Cooling water-saturated blends turns them hazy because some of the water becomes insoluble. However, the water that is released does not contain much ether and there is not enough water to cause performance problems.

The situation is different for gasoline oxygenated with 10 vol % ethanol. The gasoline-alcohol blend can dissolve more water (6000–7000 ppm at 21°C/70°F). When this blend is cooled, both the water and some of the ethanol become insoluble. Contacting the blend with more water also draws ethanol from the blend. The result, in both cases, is two layers of liquid: an upper ethanol-deficient gasoline layer and a lower ethanol-rich (up to 75% ethanol) water layer. The process is called phase separation and it occurs because ethanol is completely soluble in water but only marginally soluble in hydrocarbons. After phase separation, the gasoline layer will have a lower octane number and may knock in an engine. The fuel also is less volatile. The engine will not run on the water/ethanol layer. As the concentration of ethanol is decreased, the aromatics content of the gasoline is decreased, and as temperature is decreased, less water is required to cause a phase separation.

The potential for phase separation requires that gasoline oxygenated with ethanol not be exposed to water during its distribution or use in a vehicle. Because of this requirement, gasoline oxygenated with ethanol is not transported in pipelines, which sometimes contain water. Rather, the ethanol is added to tanker trucks at the terminal immediately before delivery to the service station. Housekeeping at the service station is very important to prevent water contamination. This water sensitivity also means that extra care should be taken when gasoline oxygenated with ethanol is used as a fuel for boat engines. Ethanol blends are hygroscopic (absorb moister from the air) and in time can phase separate during storage if the tank is vented to the atmosphere and is subject to breathing as a result of temperature changes.

Thus water separators in your larger boats along with your fuel filters.

As for the “GOO” I mentioned: "Microbial Growth" Avgas is sterile when first produced because of the high refinery processing temperatures. But it becomes contaminated with microorganisms that are always present in air and water. These include bacteria and fungi (yeasts and molds). The solids formed by biogrowth are very effective at plugging fuel filters. Some microorganisms also generate acidic by-products that can accelerate metal corrosion.

Since most microorganisms need free water to grow, biogrowth is usually concentrated at the fuel-water interface, when one exists. Some organisms need air to grow (aerobic organisms), while others grow only in the absence of air (anaerobic organisms). In addition to food (fuel) and water, microorganisms also need certain elemental nutrients. Phosphorus is the only one whose concentration might be low enough to limit biogrowth. Higher ambient temperatures also favor biogrowth.

Microbial contamination of avgas is less common than in other petroleum products, presumably due to the toxicity of tetraethyl lead, but it does occur. The best approach to microbial contamination is prevention. And the most important preventive step is keeping the amount of water in the fuel storage tank as low as possible. No additives are approved as biocides in the major

4. Ethanol has a slightly lower energy content than gasoline, so you will get a little less mileage with ethanol.

Correct because ETOH doesn’t have the same amount of energy stored in it as gas does.

As a side note if your boat was made pre 91 and has a fiberglass tank in it you might want to think twice about running corn gas through it. The glass and the ETOH don’t play well together and have a tendency to make things that plug your fuel filter.

Foot Notes Foot Notes

Foot Note

[spearchucker]

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1. Ethanol increases the octane of fuel, so therefore you don't need a higher octane if using ethanol blended fuel.

I beg to differ with you . The octane number scale is defined by two pure chemical reference fuels: normal heptane (n-heptane) with an octane number of zero, and isooctane (2,2,4-trimethylpentane) with an octane number of 100. The octane number of a blend of these two compounds is equal to the volume percentage of isooctane it contains. Isooctane also defines 100 on the performance number scale. The performance number scale above 100 is defined by mixtures of isooctane and tetraethyl lead.

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All of this is true, but Ethanol still has a higher octane rating/number than pure gasoline, so therefore it will increase the octane rating of a fuel by blending with it. Not sure what you are getting at here...

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3. Ethanol doesn't have "goo" in it. It will turn to "goo" if it sits for too long in an unsealed can. It will collect water which is what the "goo" is. If I used ethanol blended fuel, I buy it in quantities that I will use up within a month. If it needs to sit longer I used non-ethanol fuel and treat it with Seafoam as a stabilizer. The only really bad thing about ethanol in small engines is that it doesn't store well for more than a month or 2.

Sorry, I disagree again~~~ "Water Tolerance" Conventional gasoline, depending on its aromatics content, can dissolve up to 150 parts per million (ppm) water at 21°C (70°F). Oxygenating gasoline with ethers can increase water solubility to 600 ppm. Contacting either conventional gasoline or ether-oxygenated gasoline with additional water will not affect the properties of the gasoline but can make it hazy in appearance.

Cooling water-saturated blends turns them hazy because some of the water becomes insoluble. However, the water that is released does not contain much ether and there is not enough water to cause performance problems.

The situation is different for gasoline oxygenated with 10 vol % ethanol. The gasoline-alcohol blend can dissolve more water (6000–7000 ppm at 21°C/70°F). When this blend is cooled, both the water and some of the ethanol become insoluble. Contacting the blend with more water also draws ethanol from the blend. The result, in both cases, is two layers of liquid: an upper ethanol-deficient gasoline layer and a lower ethanol-rich (up to 75% ethanol) water layer. The process is called phase separation and it occurs because ethanol is completely soluble in water but only marginally soluble in hydrocarbons. After phase separation, the gasoline layer will have a lower octane number and may knock in an engine. The fuel also is less volatile. The engine will not run on the water/ethanol layer. As the concentration of ethanol is decreased, the aromatics content of the gasoline is decreased, and as temperature is decreased, less water is required to cause a phase separation.

The potential for phase separation requires that gasoline oxygenated with ethanol not be exposed to water during its distribution or use in a vehicle. Because of this requirement, gasoline oxygenated with ethanol is not transported in pipelines, which sometimes contain water. Rather, the ethanol is added to tanker trucks at the terminal immediately before delivery to the service station. Housekeeping at the service station is very important to prevent water contamination. This water sensitivity also means that extra care should be taken when gasoline oxygenated with ethanol is used as a fuel for boat engines. Ethanol blends are hygroscopic (absorb moister from the air) and in time can phase separate during storage if the tank is vented to the atmosphere and is subject to breathing as a result of temperature changes.

Thus water separators in your larger boats along with your fuel filters.

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Why do you disagree with me? Your lengthy comments copied from the Chevron HSOforum support what I said in a few sentences... Ethanol absorbs water and doesn't store for more than a month or 2. The "goo" you are referring to comes from old hardware degradation that is not ethanol compatible or as a result of dump growing in the fuel because of the water that was absorbed.